The objective of this project was to examine the effect of age on absorption of fat-soluble and water-soluble vitamins. Female Wistar rats, aged 6, 12, and 24 months were orally administered radioactive forms of vitamins A and D and were sacrificed 18 hours later. A second group of 6, 12, and 24 month old rats were also orally administered radioactive B12 and niacin and sacrificed 16 hours later. In both experiments, the esophagus, stomach, small intestinal wall, contents of the small intestine, cecum, colon, and collected feces were assayed for isotope. Liver and plasma levels of the administered vitamins were also determined at sacrifice. Absorption of each of the vitamins was unaffected by age. Plasma and liver levels of the isotope at sacrifice were also not related to the age of the animals.